Heat oven to 350 degrees. Grease a 9x9x2 pan, I always use cooking spray.
In a small sauce pan, thoroughly blend raspberry-lemonade concentrate with cornstarch. I add a little sugar, about a teaspoon or two, to make it a little sweeter. Heat until mixture thickens and boils, stirring occasionally. Remove from heat and cool slightly. Cool slightly, about 5 min. Pour glaze into prepared pan and distribute even to cover bottom of pan.
Prepare brownie mix, following package directions. Gently, pour batter over glaze, spreading evenly, be careful not to disturb glaze. Bake for 25-30 minutes or until brownies are done.
Cool pan completely before cutting. While brownies are cooling, I mash thawed raspberries in a bowl with a tablespoon or two of confectioners sugar, very delicious, and set aside. When cutting brownies, use a wet knife, repeatedly rinsing knife, as necessary, to keep crumbs from building up and tearing the brownies. Invert each brownie onto a plate and mashed raspberries and whipped.